Extrahepatic alveolar echinococcosis without liver involvement: a rare manifestation.

BACKGROUND: Alveolar echinococcosis (AE) primarily affects the liver and extrahepatic disease is considered the consequence of a secondary infection via metastatic spread from the hepatic focus. PATIENTS: Two patients with extrahepatic AE without liver involvement are presented. The first case is a patient with AE of the spleen and a small pulmonary calcification. In the second case exclusive affection of the spine was observed. DISCUSSION: Various pathogenetic explanations for hepatic omission appear plausible: a passage of oncospheres through hepatic sinuses without causing disease, a passage via lymphatic vessels or via portocaval anastomoses and the vascular passage in a retrograde fashion. Extrahepatic manifestation of AE without apparent liver involvement is rare. However, AE should be taken into account among other differential diagnoses even in cases of extrahepatic lesions without liver involvement.